Topic: General Weather Thread: QLD / NSW / ACT / NT

[Mike]

and this (courtesty WZ & ABC.)

The NT Weather Bureau says it expects a warmer than usual build-up this year.

The manager of climate services Sam Cleland says it's difficult to predict how much warmer the build-up could be, but points out higher than usual temperatures in the Indian Ocean should have a flow-on effect in the Territory, particularly the Top End.

"When we've had patterns like this, about six or seven out of ten build-ups, or October to December periods, have been warmer than normal.

"So it's a reasonable expectation that this one probably will be."

The bureau is also predicting two to three cyclones in the Top End this year but says that's not out of the ordinary.

"The thing that often dictates the nature of cyclone season is that El Nino/La Nina cycle and we are in a neutral phase of that so we're not expecting anything out of the ordinary."

The build-up marks the end of the dry season, which officially ended yesterday when the Darwin Airport rain guage reported it's first readings in a record breaking 167 days.

- ABC  © ABC 2008

Their comments confirm my last thread regarding the sizzler days and the haphazard seasons of late.

The majority of our storms are single air mass types, but we get good days when they are widespread and stronger - a mixed bag of storms depending on the day.  As Nick Moir found out, it's really difficult to find decent storms that survive, where they will be let alone trying to chase the buggers.  Makes for interesting busts!

No shortage of lightning here as you would expect with the CAPE levels.  From memory we only had 2-3 SWW events and really they did not amount to much by the time they reach 40km from Darwin.  The early morning squall lines are the ones to chase as the sea breeze has a positive influence on them as opposed to the regular negative influence during daytime hours.  The breezes seem to up the temperature within a 40km area from Darwin and has a 'drying' affect on outflow moisture - you can see it clearly when morning to early arvo clouds convect thickly and by late arvo there's a visible blue sky barrier between the city and rural areas once the sea breeze flows outward - it's disheartening to see the CUs burn away in front of one's eyes!


But the structures are very nice and wonderfully photogenic due to their size.  I had a couple from NSW chase last year here and they were just astounded with the number of storms they could actually choose from to chase - their structure left them with a great impression because they were so different compared to the big supercells and storms you guys get in NSW.

A bit like grapefruit to peanuts but they're tropical by nature and one can't expect anything else.

[Harley Pearman]

Mike

Thank you. It is interesting watching the storms develop during October and November or the beginning of the wet season. I noted when living in Darwin that the afternoon ones were always the pulse variety but they would form inland east or south east of Palmerston or to the east around Adelaide River etc. They would travel a distance but collapse as they approached Darwin proper. Others did not move at all. They just dumped rain in an area then weaken. Roads are also difficult too up there and chasing them can be difficult too.

No doubt the same will occur again this October / November.

Actually Australian Geographic Volume 48 October 1997 has done an excellent article titled, Hunting Hector centred on storm chasing and the science of Hector around Darwin and Melville Island and the dynamics of it. The research was titled - The Maritime Continent Thunderstorm Experiment (MCTEX) where 50 atmospheric scientists assembled in Darwin in 1995 to monitor the early build up of Hector and to find out how this storm complex works.

It has allot to do with the collisions of boundaries being sea breezes and land breezes. for example it was learnt that:-

- If there is a northerly on Melville Island, the southern sea breeze will become very strong producing a storm on the south coast of the island.

It was also found that:-

- Early thunderstorms may be weak but the thunderstorm sea breeze interaction can produce a storm cell towering 18 km and dominating the island during the peak of the day.

During the experiment, rotating updrafts were observed under the strongest thunderstorms.

Some secrets of Hector were given up. Around Darwin, the sea breeze would have to play some role where a storm would develop and how it would play out.

That experiment (MCTEX) and the findings may be of interest to you as it helped to unlock some secrets of Hector during the build up.


Harley Pearman

[Mike]

Hi Harley, and yes spot on with all your comments.  We've had around 200 combined NASA and NOAA scientists in the last few years monitoring Hector and doing fly-through's with their 'Falcon' jet aircraft.  The do figure 8's around the storm and gradually encircle the top and then out again to monitor aerosol contents in the atmosphere through the updraughts he has. Last season he topped 22+km on one day which was a spectacular sight.  He's been around of late, displaying a very weak but thin tower & large anvil, but as the season progresses he'll be more structured and 'thicker' in appearance.

The storm motion has not changed since you were last here - it's a given really.  The sea breeze usually stuffs things up but as mentioned previously it can really aid storms that form within 10km of Darwin, they are strong, tall and push out dazzling positive strikes.  I recall last year a storm flanged out no less than 5 big positive strikes arched from the anvil top, outward and grounded easily 5km out from the tower - I remained in the car to photograph it because it was just so dangerous after viewing more than two within 20 seconds of each other and missed them all, but after waiting till it settled down (as they were in my vicinity) I popped the camera onto the window edge and got this from that very storm.

[Harley Pearman]

September weather features for Blacktown 2008

The first half of the month where I live were characterised by cooler than normal conditions while the second half saw temperatures rise to average or exceed the average on several days.

It is noted that:-

There were 10 days when temperatures failed to reach 20C but 5 days saw temperatures reach 30C. There were significant maximum temperature ranges between the coldest day on the 6 being 14.5C and the hottest day on the 28 being 33C.

Average Max is 21.2C (This September it was 22.6C so average maximum temperatures finished being 1.4C above average).

This is more significant given that August was a colder than normal month. Actually it is a 5C rise on August so it is a big increase from August to September.

Night time minimums were near the average being 9.3C.

It rained on 7 days producing 68 mm. Majority of that fell on the period 4 to 6 September. Prospect had 50 mm on 9 days and Seven Hills scored 66 mm.

Rainfall was above average for September.

Thus it was a warmer but wetter month than normal.

There was 1 thunderstorm that produced small but brief hail on the late afternoon of 14/9/08.

I did not observe any fog during the month.

Harley Pearman

[Harley Pearman]

Early hot spell October 2008

Certainly worth a post considering that on the 2 and 3 October 2008, maximum daily temperatures exceeded 38 degrees or 100F at a number of centres in north west New South Wales being:-

Bourke 38.8C and 37.5C on the 2 and 3.
Brewarrina 38.1C on the 2/10/08.
Tibooburra 38.4C and 38.1C on the 2 and 3.
Wanaaring 38.8C and 38.4C on the 2 and 3 plus 37.5C on the 5.

This is a hot start to October in North west New South Wales.

Actually it reached 36.9C at Sydney Airport and 36C at Sydney Olympic Park on the 3 and 34.7C where I live.

Amazingly it reached just 19C on the 5/10/08 where I live due to the southerly change and very low cloud cover.

Yet what was unique on the 5/10/08 is that maximum temperatures were warmer at Katoomba (19.7C) and at Lithgow (22C) than at Blacktown which I certainly noticed when driving through these areas. The southerly change created an interesting variation in maximum temperatures in coastal areas when compared to places inland and higher up in elevation.

Harley Pearman

[Steven]

The weather has been so muggy today, the temp topped out at 30C shortly after 10:30am and the humidity was upwards of 70% for most of the day - Yuck.

[Steven]

Wow. There is some really good instability progged for next week on GFS but sadly it keeps changing with every update. Sheer though seems to be the only real let down.

[Rhett Blanch]

Have put together some charts using the BOM's Daily Weather Observation data.  The following shows temperatures in Sydney Sept - November.  You can see the obvious see-saw in temperatures for this period when compared to the rest of the year with temps heating up as the fronts approach then the sudden change of temp as they pass. 

Source: http://weather.wilgatree.com/recent-weather/?filter=Sydney&id=IDCJDW3082

If you trawl around nearby locations it is interesting to observe how this effect is even more pronounced (higher max temps) at Homebush and Penrith.

[Harley Pearman]

Rhett

Thanks for posting that graph. In October 2008 I certainly noticed the large swings in maximum daily temperature where I live in Blacktown. For example:-

It reached a maximum of 30 degrees on 7 days during the month with the hottest being the 31 when it reached 35C. At the other extreme, it failed to reach 20C on 5 days.

For the rest of the time, the maximum temperatures fell between 20c and 29C.

The 30 degree days have to date preceded the next cool change and so far this spring, only one or two such days in a row have occurred prior to the arrival of the next cool change.

In one instance such as the 3, it reached 34C but the next day the maximum temperature was 20C. In another instance on the 27, it reached 34C but 2 days later, the maximum temperature was just 17C.

Maximum daily temperature swings or fluctuations were large again from 14.5C on the 6 to 35C on the 31. It lends support to the graph that you found.

The average maximum for October where I live is 23.6C but in 2008, it was 25.2C being 1.6C above average. Thus it was still a warmer month than normal.

The average minimum is 12.1C but this year was 15.9C (Well above average).

Amazingly, the rainfall was 53.5 mm which is reasonably close to the long term average of 59mm and rain fell on 10 days including 4 thunderstorms. There was also one fog on the 12.

So during September and October, it reached 30 degrees on 12 days and the tally from 1 September to 16 November currently stands at 16 days (Blacktown tally). As shown, there have been large swings in maximum daytime temperatures again this spring.

Harley Pearman

[Harley Pearman]

November weather conditions for home (Blacktown) 2008

Further to this thread, November where I live is best described as "Warm and moist" as shown:-

Av Max 25.4C (Normal maximum averages 25.2C). Roughly average.
Av min 14.5C (Normal minimum averages is 14.1C). Slightly above average.

There were 3 days when it reached 30 degrees. Actually, this is less than September and October when there were 5 and 7 days respectively. Quite amazingly, the average maximum temperature was almost the same as October 2008.

There were 15 days in spring when it reached 30C Celsius.

As generally highlighted by the graph in a previous post, large temperature swings continue from 20C on the 4 to 35.8C on the 14 but for the first time this season, no single day recorded a maximum temperature below 20C.

Rainfall - 73 mm on 10 days at Prospect.
Where I live - 75.8 mm fell over 9 days.

There were 4 thunderstorm days but a total of 6 storms occurred with one producing hail up to 2 cm (brief fall of flat shaped hail on the 29/11/08) and another brought strong gusty winds and a brief power blackout 19/11/08. The storm on the 19/11/08 brought the heaviest single rainfall event of the month being 32 mm.

There were no fogs.

Harley Pearman

[Mike]

Current pea soup conditions.

Weather here is quite atrocious as far as any decent storms.  Although we have a trough over the Top End and connected to a weak but maturing monsoon trough with embedded low near the Kimberley region things are quite messy.  The low is not expected just yet to form into anything significant, although Thursday looks like the betting day for the formation of a cyclone perhaps.

There's been showery thunder type weather of late.  One or two half decent storms in clean air during the day but by nightfall a lot of cloud blnakets the region and the storms that are in them are weak and quickly dissipate.  You'd be lucky to catch a single clean CG amongst all the quick flash and rumble and annoying shower activity is always a pain.  Quite a lot of moisture in the soundings of late and for me it's this type of weather I do not particularly worry about with regards to chasing.  Widespread storms/showers may sound appealing, but as far as chasing...mmm not for this black duck.  I'd much prefer it when I can see structure and know what condition or stage the storms are at, at least it gives me something to evaluate.

The rest of this week sees not much change in the forecasts and the steering of storms and lines changes daily now, either from the NW/NE and the presence of convergence areas inland always draw the storms to it - last night was no different.  An inland low was pulling the storms during the night to the SW and then swung them around to the W/NW.  What's difficult is seeing nothing on radar or by observation during the night and then 10 minutes later there's a bunch of cells forming where you just looked - lots of nice colors on the radar but not enough to convince me that there's any storms that will stay 'up' and produce some really visible lightning.

Apart from all that it's much the muchness with the monsoon lingering and you have to be in the right place and the right time - often by chance - to nab some CG's.

Here's another spout photographed 14 December at Lee Point - not far from Darwin - photo credited to Nolan Caldwell who was out that way waiting for God knows what as he primarily is a nature photographer!  He likes the storms though since meeting me and has nabbed some corker shots - this one is quite envious!


Courtesy:  Nolan Caldwell

[Harley Pearman]

Weather review for December 2008 (Blacktown)where I live

The weather for December 2008 where I live is shown below:-

Average Maximum 28.6C (Long term average 27.4C) - 1.2C above average.
Average Minimum 15.8C (Long term average 16.4C) - Minus 0.6C below average.

Compared to December 2007:

Average Max 26.1C. Average Min 16.5C.

The daily maximums were 2.5C warmer but the nights were 0.7C cooler when a comparison is made to December 2007.

There were 14 days when it reached 30C (December 2008). In December 2007, there were 6 days. The hottest day was 6/12/08 when the maximum temperature reached 35C and coldest day was 11/12/08 when the maximum temperature was 19C.

So far since 1/9/08 to 31/12/08, it has reached 30C on 29 days.

There were 4 thunderstorms during the month but on the 28 and 29, thunder was audible from two storms that passed to the north and south of Blacktown City.

On the 9/12/08, substantial morning fog was observed which is a rare event for December.

Rainfall

At Prospect, 71.5 mm fell on 11 days but where I live, the rainfall was lower at around 63 mm across 10 days. That can be explained when on the 28, a thunderstorm and shower passed over Prospect but missed Blacktown city and immediate surrounds.

When compared to December 2007, 103 mm of rain fell over 14 days. Thus December 2008 was drier than December 2007.

In 2008, 914 mm of rain fell at Prospect on 134 days.
Where I live, approximately 880 mm fell on 114 days.

In 2007, 1,050 mm fell and in 2006, 607 mm fell. February 2008 was the wettest month with 233 mm of rain and May was the driest month with 3.1 mm.

Southerly change:

Of interest as I prepare this, a strong southerly change is moving north along the New South Wales South Coast with interesting temperature gradients. At 2 pm, the temperature was nudging 21C at Merimbula and Bega and barely 19C at Gabo Island in cool SSE winds. Sydney being north of the cool change is experiencing 32C to 34C. That shows a strong temperature gradient as much as 15C across the southerly change boundary.

Harley Pearman

[Harley Pearman]

Hot weather for SE Australia 5 to 7 January 2008:

This is worth a post because a surge of hot air has progressed into south east Australia and temperatures in the high 30s and low 40s have been occurring or are expected to occur during this period in many areas of NSW.

On 5/1/2009, Penrith in western Sydney reached a peak of 39C and on 6/1/2009, the expected forecast maximum for Penrith is 41C.

Where I live in Blacktown, it reached 38C on 5/1/2009 and on 6/1/2009, the expected forecast maximum is in the order of 39C to 40C.

The last time such temperatures were recorded in the Sydney basin was on 21 January 2007 when it topped out at 41C where I live and including other inland Sydney suburbs.

This appears to be the strongest burst of summer heat to reach the Sydney Basin in almost 2 years.

Similar temperatures occurred in many areas of inland NSW 5/1/2009 and again forecast for 6/1/2009.

A southerly change on Thursday will end the hot spell in the southern areas.

Harley Pearman

[Kristy Norman]

It is also looking to be a pretty hot week over here in the Mid West. The small inland town of Mullewa, which is 92 kms ENE of Geraldton have the next six days forecasted between 41 and 45 degrees! Yesterday made it to 42.5, and so far this month (only five days in) they have not had a day below 40.0.
Here on the coast we are looking at mid to low 30s, thanks mostly to the roaring southerly seabreeze.

[Ursula]

a blast from the past, mid February we had a week of 40's, 45 on one day, that was in 1971, my son was born 28.1., I sat in the bath with him all day to keep cool, one couldn't touch the door handles in the house, it was in Lansvale NSW on the Prospect River, the heat wave broke with a hail storm, about 5-8cm from memory, did a lot of damage to the car yards on the Hume highway.